We purchased this carrier in anticipation of flying with our cat for a long trip over the holidays. Like many other people on this and other sites, we fretted about the airline's size and weight requirements, since this carrier was an inch longer than the required size and with the cat, very close to the 20lb weight requirement for US Airways. We should not have worried as no one measured anything. It fit fine under the seat, even on a pretty small plane (Canadair Regional Jet). The inch long "violation" means it extends into your footspace an inch more than it should - worth it for the animal's comfort, since I wasn't going to be comfortable even if I did have that inch.This carrier is well designed on a number of levels. Most importantly, the shoulder strap attaches to the carrier in two conformations so you can carry it in the pictured way (wide and low) or on its side (tall and narrow). Tall and narrow was much more maneuverable in the airport and helped us finesse the "stand up and turn around" requirement. It's very sturdy, particularly the mesh windows which appear to have a kind of wire mesh behind the black netting, which I presume makes it more claw-resistant. The two entryways (top and side) were convenient for getting the cat out for security screening, since she really didn't want to leave this carrier. I think that's partially because it's fairly snug in there (good for cats, who like to feel protected, but not for dogs, who need more space) and partially because we familiarized her with the carrier, with treats afterwards, for a few weeks beforehand. The side pocket is perfect for her payment certificate, vet certificate, and a small bag of treats, but nothing larger.In short, this carrier is spendy, but it's a Cadillac. It was such a good experience that I will probably travel with her again the next time I go to a cat friendly location.